Atmosphere gaseous composition

Mirtov, B. A. (1961) Gaseous Composition of the Atmosphere and its Analysis (in Russian). Moscow. 

The oxidation of propylene oxide on porous polycrystalline Ag films supported on stabilized zirconia was studied in a CSTR at temperatures between 240 and 400°C and atmospheric total pressure. The technique of solid electrolyte potentiometry (SEP) was used to monitor the chemical potential of oxygen adsorbed on the catalyst surface. The steady state kinetic and potentiometric results are consistent with a Langmuir-Hinshelwood mechanism. However over a wide range of temperature and gaseous composition both the reaction rate and the surface oxygen activity were found to exhibit self-sustained isothermal oscillations. The limit cycles can be understood assuming that adsorbed propylene oxide undergoes both oxidation to CO2 and H2O as well as conversion to an adsorbed polymeric residue. A dynamic model based on the above assumption explains qualitatively the experimental observations. 

Atmospheric precipitation, in the form of snow and ice, has accumulated continuously for thousands of centuries on polar ice caps. The snow density at the surface is about 0.3 g cm and it increases with depth below the so-called close-off depth the firn (snow with density higher than 0.4 g cm"" ) turns into ice (density 0.83 g cm ). At this depth (between 95-115 m in the central east Antarctica) air in the pores of the firn gets trapped in ice as bubbles preserving fascinating information on the gaseous composition of past atmospheres (12-16). 

Davitaya, F. F., 1971 History of the atmosphere and dynamics of its gaseous composition (in Russian). Meteorol. i Gidrol. 2, 21-28. 

This report deals with the dynamic response of the solid-state gas sensors when the gaseous composition of the atmosphere is intentionally varied. The study is focused on the featuring of the chemical composition of the atmosphere using the information extracted from the transients of the response. Theoretical analysis of the surface processes in the sensors is aimed at a description of the response kinetics by a set of the parameters acceptable for the featuring of an odour. The method was tested by experimental investigations of the response kinetics under exposure to various volatile compounds including that Ifom TNT based explosives. 

Source B. A. Miitov, "Gaseous composition of the atmosphere and its analysis/ Akad. Nauk. SSSR, Inst, Prikl. Geofiz Moskva (translated by the Israel Program for Scientific Translations, published in Washington, U.S. Dept, of Commerce, Office of Technicaf Services, JS6J, 209 pp.). 

On earth, as in the atmosphere, gaseous processes took place by dissociation into atoms, but in mineral generation that state was only a prelude to chemical composition. 

Much of the gas and oil released as a result of nuclear attacks will bum. This is another source of copious amounts of particulate matter in the atmosphere. However, it is also likely that a fraction of the gas would escape unbumed to the atmosphere where it would be gradually broken down by photochemical reactions. Much of the escaping oil may likewise bum, but an appreciable portion of it may volatilize as in the Ixtoc 1 blowout in the Gulf of Mexico, which resulted in the world s largest oilspill. In this case it is estimated that only 1 % of the oil burned, while 50-70 % evaporated [27]. We next consider the influence of these emissions on the gaseous composition of the atmosphere. 

Plasma arc-jet and oxyacetylene torch ablation tests are much more convenient for operations and with much lower cost, which therefore are often used for primary evaluations of materials about their thermal shock resistance and ablation resistance properties . The difference between these two methods is their gaseous composition and flow speed. A plasma of air may exhibit ultra high temperatures above 5000°C and high velocities of 2 Mach but with ionized air atmosphere. On the other hand, the generally used oxyacetylene torch is of combustion gaseous products of carbon mono/dioxide, water vapor, OH and active hydrocarbon species with gas velocity less than 1 Mach and temperatures above 3000°C. A HVOF torch exhibits... 

The short-term exposure of humans, animals, and plants to gaseous pollutants is more severe than that for pollutants in other matrices. Since the composition of atmospheric gases can show a substantial variation over a time, the continuous monitoring of atmospheric gases such as O3, CO, SO2, NH3, H2O2, and NO2 by in situ sampling is important. 

Vacuum and Atmosphere Melting. A coreless high frequency induction furnace is enclosed in a container or tank which can be either evacuated or filled with a gaseous atmosphere of any desired composition or pressure. Provision is made for additions to the melt, and tilting the furnace to pour its contents into an ingot mold also enclosed in the tank or container without disturbing the vacuum or atmosphere in the tank (Fig. 2). 

Aerosol Dynamics. Inclusion of a description of aerosol dynamics within air quaUty models is of primary importance because of the health effects associated with fine particles in the atmosphere, visibiUty deterioration, and the acid deposition problem. Aerosol dynamics differ markedly from gaseous pollutant dynamics in that particles come in a continuous distribution of sizes and can coagulate, evaporate, grow in size by condensation, be formed by nucleation, or be deposited by sedimentation. Furthermore, the species mass concentration alone does not fliUy characterize the aerosol. The particle size distribution, which changes as a function of time, and size-dependent composition determine the fate of particulate air pollutants and their... 

In Table I are shown representative data concerning plasma deposition of a-C(N) H films, produced by different methods and under different gaseous mixtures and deposition parameters. In this table are displayed data on chemical composition (maximum N content, and range of variation of H content), deposition details (deposition pressure, self-bias, and atmosphere composition), and the method used for chemical composition determination. 

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